Im stupid, forget that there is in - game options. Thanks!

Hello guys! I'm new here so first of all i would like to say hello to all players of good, ol diablo. :) I've got this problem - dl'ed belzebub, unzipped it, copied to diablo folder - everythings fine except for fact that diablo is running in windowed mode and dunno how to fix it. Any ideas? I got w...